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61.
Solmaz A Aytun T Deuschle JK Ow-Yang CW 《Langmuir : the ACS journal of surfaces and colloids》2012,28(28):10592-10596
Tapping mode atomic force microscopy (TM-AFM) enables mapping of chemical composition at the nanoscale by taking advantage of the variation in phase angle shift arising from an embedded second phase. We demonstrate that phase contrast can be attributed to the variation in elastic modulus during the imaging of zinc acetate (ZnAc)-loaded reverse polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) diblock co-polymer micelles less than 100 nm in diameter. Three sample configurations were characterized: (i) a 31.6 μm thick polystyrene (PS) support film for eliminating the substrate contribution, (ii) an unfilled PS-b-P2VP micelle supported by the same PS film, and (iii) a ZnAc-loaded PS-b-P2VP micelle supported by the same PS film. Force-indentation (F-I) curves were measured over unloaded micelles on the PS film and over loaded micelles on the PS film, using standard tapping mode probes of three different spring constants, the same cantilevers used for imaging of the samples before and after loading. For calibration of the tip geometry, nanoindentation was performed on the bare PS film. The resulting elastic modulus values extracted by applying the Hertz model were 8.26 ± 3.43 GPa over the loaded micelles and 4.17 ± 1.65 GPa over the unloaded micelles, confirming that phase contrast images of a monolayer of loaded micelles represent maps of the nanoscale chemical and mechanical variation. By calibrating the tip geometry indirectly using a known soft material, we are able to use the same standard tapping mode cantilevers for both imaging and indentation. 相似文献
62.
CaGe(3) has been synthesized at high-pressure, high-temperature conditions. The atomic pattern comprises intricate germanium layers of condensed moleculelike dimers. Below T(c) = 6.8 K, type II superconductivity with moderately strong electron-phonon coupling is observed. 相似文献
63.
Prof. Dr. Alim Abdurahman Jingmin Wang Yihan Zhao Dr. Ping Li Dr. Li Shen Prof. Dr. Qiming Peng 《Angewandte Chemie (International ed. in English)》2023,62(15):e202300772
It is very challenging to obtain stable room-temperature luminescent open-shell singlet diradicals. Herein we report the first stable Müller's hydrocarbon TTM-PhTTM with luminescent properties. Variable-temperature electron paramagnetic resonance spectroscopy measurements and theoretical calculations show that TTM-PhTTM has an open-shell singlet ground state with a diradical character of 90 %. Because of a small singlet-triplet energy gap, the open-shell singlet ground state can be thermally excited to a triplet state. TTM-PhTTM shows room-temperature deep-red emission in various solutions. Unusually high stability of TTM-PhTTM was also observed owing to effective steric hindrance and spin delocalization. Our results are beneficial to the rational design and discovery of more stable luminescent diradical materials. 相似文献
64.
Roman Gumeniuk Walter Schnelle Ulrich Burkhardt Horst Borrmann Michael Nicklas Alim Ormeci Miroslav Kohout Andreas Leithe-Jasper Yuri Grin 《ChemInform》2015,46(36):no-no
The crystal and electronic structure, chemical bonding, and physical properties of ThPt2 are characterized by powder XRD, magnetic, electrical resistivity and specific heat measurements, and by DFT scalar-relativistic electronic structure calculations. 相似文献